Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/54—Silicon-containing compounds
  • C08K5/548—Silicon-containing compounds containing sulfur
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
  • Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction 

Definitions

• the present invention relates to diene rubber compositions reinforced with an inorganic filler such as silica, used in particular for the manufacture of tires or semi-finished products for tires such as treads.
• vulcanization of diene elastomers by sulfur is widely used in the rubber industry, particularly in the tire industry.
• a relatively complex vulcanization system comprising, in addition to sulfur, various vulcanization accelerators as well as one or more vulcanization activators, in particular zinc derivatives such as zinc oxide (ZnO) is used.
• zinc derivatives such as zinc oxide (ZnO)
• ZnO zinc oxide
• zinc salts of fatty acids such as zinc stearate.
• a medium-term objective for tire manufacturers is to remove zinc or its derivatives from rubber formulations, because of the known environmental impact of these compounds, particularly with respect to water and aquatic organisms ( classification R50 according to European Directive 67/548 / EC of 9 December 1996).
• the invention also relates to a method for preparing a rubber composition based on a diene elastomer and a reinforcing inorganic filler, free or containing less than 0.5 phr of zinc and having a processability in the raw state improved process, characterized in that at least one diene elastomer, at least one inorganic filler as a reinforcing filler, a silane-polysulfide of formula (I) and from 0 to less than 5 phr are incorporated by kneading into at least one diene elastomer; of carbon black.
• the invention also relates to the use of a composition according to the invention for the manufacture of finished articles or semi-finished products, as well as these finished articles and semi-finished products themselves, comprising a composition of according to the invention, these articles or semi-finished products being intended for all "systems of ground connection” (or “suspension systemis” ) of motor vehicles, such as pneumatic, internal safety supports for tires, wheels, springs rubber, elastomeric joints, other suspension elements and anti-vibration.
• systems of ground connection or "suspension systemis”
• motor vehicles such as pneumatic, internal safety supports for tires, wheels, springs rubber, elastomeric joints, other suspension elements and anti-vibration.
• the subject of the invention is particularly the use of a rubber composition according to the invention for the manufacture of tires or semi-finished rubber products intended for these tires, these semi-finished products being chosen in particular from group consisting of the treads, the sub-layers intended for example to be placed under these treads, the crown plies, the flanks, the carcass plies, the heels, the protectors, the inner tubes and the inner waterproof packings for tire without a chamber.
• composition according to the invention is particularly suitable for the manufacture of tire treads intended to equip passenger vehicles, light trucks, 4x4 vehicles (four-wheel drive), two-wheelers, "heavy vehicles” (this is ie subway, bus, road transport equipment (trucks, tractors, trailers), off-the-road vehicles), aircraft, civil engineering, agrarian, or handling equipment.
• the invention also relates to these ground connection systems of motor vehicles, these tires and semi-finished rubber products themselves, including treads, when they comprise a rubber composition according to the invention.
• the invention particularly relates to the use of such treads for the manufacture of new tires or the retreading of used tires.
• the invention also relates to these ground connection systems for motor vehicles, tires and treads both in the green state (ie, before firing) and in the fired state (ie, after crosslinking or vulcanization).
• the rubber compositions are characterized, before and after firing, as indicated below.
• the Mooney plasticity measurement is carried out according to the following principle: the raw composition (i.e., before firing) is molded in a cylindrical chamber heated to 100 ° C. After one minute of preheating, the rotor rotates within the test tube at 2 revolutions / minute and the useful torque is measured to maintain this movement after 4 minutes of rotation.
• the measurements are carried out at 130 ° C., in accordance with the French standard NF T 43-005.
• the evolution of the consistency index as a function of time makes it possible to determine the toasting time of the rubber compositions, evaluated according to the above-mentioned standard by the parameter T5 (case of a large rotor), expressed in minutes, and defined as being the time required to obtain an increase in the consistometric index (expressed in MU) of 5 units above the minimum value measured for this index.
• the Shore A hardness of the compositions after curing is assessed according to ASTM D 2240-86.
• the dynamic properties ⁇ G * and tan ( ⁇ ) max are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard.
• the response of a sample of vulcanized composition (cylindrical specimen 4 mm in thickness and 400 mm 2 in section), subjected to a sinusoidal stress in alternating simple shear, at the frequency of 10 Hz, is recorded under normal conditions. temperature (23 ° C) according to ASTM D 1349-99, or as the case may be at a different temperature.
• a strain amplitude sweep is performed from 0.1% to 45% (forward cycle) and then from 45% to 0.1% (return cycle).
• the term "practically free" composition of zinc or zinc derivative must be understood to mean a composition comprising at most a negligible amount of zinc or zinc derivative, that is to say such that its weight content of zinc is less than 0.5 phr, preferably less than 0.3 phr. More preferably, the composition of the invention is devoid (i.e., completely free) of zinc (or zinc derivative), in other words its zinc content is zero (0 phr).
• compositions of the invention are therefore based on at least: (i) a (at least one) diene elastomer, (ii) a (at least one) inorganic filler as a reinforcing filler, (iii) a (at least one) a) silane-polysulfide of formula (I) as inorganic filler / diene elastomer coupling agent, and (iv) 0 to less than 5 phr of carbon black.
• composition based on is meant in the present application a composition comprising the mixture and / or the reaction product of the various constituents used, some of these basic constituents (for example the coupling agent and the inorganic filler) being capable of, or intended to react with, each other, at least in part, during the various phases of manufacture of the compositions, in particular during of their vulcanization (cooking).
• these basic constituents for example the coupling agent and the inorganic filler
• elastomer or rubber (both terms being synonymous), of the "diene” type, is generally meant an elastomer derived at least in part (ie a homopolymer or a copolymer) from monomers dienes (monomers carrying two carbon-carbon double bonds). carbon, conjugated or not).
• diene elastomers in known manner, can be classified into two categories: those said to be “essentially unsaturated” and those termed “essentially saturated”.
• essentially unsaturated diene elastomer is meant a diene elastomer derived at least in part from conjugated diene monomers having a level of units or units of diene origin (conjugated dienes) which is greater than 15% (mol%); for example, diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins of the EPDM type do not fall within this definition and may instead be described as essentially saturated diene elastomers. "(low or very low diene origin, always less than 15%).
• the term “highly unsaturated” diene elastomer is particularly understood to mean a diene elastomer having a content of units of diene origin (conjugated dienes) which is greater than 50%.
• diene elastomer any type of diene elastomer, one skilled in the art of the tire will understand that the present invention is preferably carried out with essentially unsaturated diene elastomers, in particular of the type (a) or (b). ) above.
• conjugated dienes 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di-alkyl (C1-CS) -1,3-butadienes, such as, for example, 2-butadiene, are especially suitable.
• Suitable vinyl aromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene and divinylbenzene. vinyl naphthalene.
• the copolymers may contain between 99% and 20% by weight of diene units and between 1% and 80% by weight of vinyl aromatic units.
• the elastomers may have any microstructure which is a function of the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the amounts of modifying and / or randomizing agent used.
• the elastomers can be for example block, statistical, sequenced, microsequenced, and be prepared in dispersion or in solution; they may be coupled and / or starred or functionalized with a coupling agent and / or starring or functionalization.
• Polybutadienes and in particular those having a 1,2-unit content of between 4% and 80%, or those having a cis-1,4 content of greater than 80%, polyisoprenes and copolymers of butadiene- styrene and in particular those having a styrene content of between 5% and 50% by weight and more particularly between 20% and 40%, a 1,2-butadiene content of the butadiene part of between 4% and 65%, a content of trans-1,4 bonds between 20% and 80%, butadiene-isoprene copolymers and in particular those having an isoprene content of between 5% and 90% by weight and a glass transition temperature ("Tg" - measured according to ASTM D3418-82) of -40 ° C.
• Tg glass transition temperature
• the isoprene-styrene copolymers and in particular those having a styrene content of between 5% and 50% by weight and a Tg of between -25 ° C. and -50 ° C.
• the butadiene-styrene-isoprene copolymers are especially suitable those having a styrene content of between 5% and 50% by weight and more particularly of between 10% and 40%, an isoprene content of between 15% and 60%.
• the diene elastomer of the composition according to the invention is chosen from the group of diene elastomers (highly unsaturated) consisting of polybutadienes (BR), synthetic polyisoprenes (IR), rubber natural (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.
• diene elastomers highly unsaturated consisting of polybutadienes (BR), synthetic polyisoprenes (IR), rubber natural (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers.
• Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-copolymers of butadiene-styrene (SBIR) and mixtures of such copolymers.
• SBR butadiene-styrene copolymers
• BIR isoprene-butadiene copolymers
• SIR isoprene-styrene copolymers
• SBIR isoprene-copolymers of butadiene-styrene
• the diene elastomer is preferably an SBR copolymer, in particular an SBR prepared in solution, preferably used in admixture with a polybutadiene; more preferably, the SBR has a styrene content of between 20% and 30% by weight, a vinyl content of the butadiene part of between 15% and 65%, a trans-1,4 content of between 15% and 75% and a Tg ranging from -20 ° C to -55 ° C, and the polybutadiene has greater than 90% cis-1,4 bonds.
• the diene elastomer is preferably an isoprene elastomer, ie a homopolymer or copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), the various isoprene copolymers or a mixture of these elastomers.
• isoprene elastomer ie a homopolymer or copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), the various isoprene copolymers or a mixture of these elastomers.
• NR natural rubber
• IR synthetic polyisoprenes
• isoprene copolymers examples include copolymers of isobutene-isoprene (butyl rubber - IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene (SBIR).
• This isoprene elastomer is preferably natural rubber or synthetic cis-1,4 polyisoprene; of these synthetic polyisoprenes, polyisoprenes having a content (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used.
• the diene elastomer may also consist, in whole or in part, of another highly unsaturated elastomer such as, for example, an SBR elastomer.
• compositions of the treads of the invention may contain a single diene elastomer or a mixture of several diene elastomers, the diene elastomer or elastomers that may be used in combination with any type of synthetic elastomer other than diene, or even with other polymers.
• elastomers for example thermoplastic polymers.
• any inorganic or mineral filler regardless of its color and origin (natural or synthetic), also called “white” charge, “clear” charge or a “non-blackfiller” charge as opposed to carbon black, which inorganic filler is capable of reinforcing on its own, with no other means than an intermediate coupling agent, a rubber composition for manufacturing a tire tread, in other words able to replace, in its reinforcing function, a conventional carbon black of pneumatic grade, in particular for tread; such a filler is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) on its surface.
• -OH hydroxyl groups
• the reinforcing inorganic filler is a filler of the siliceous or aluminous type, or a mixture of these two types of filler.
• the silica (SiO 2 ) used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface and a CTAB specific surface area both less than 450 m 2 / g, preferably 30 to 400 m 2 / g.
• Highly dispersible precipitated silicas are preferred, particularly when the invention is used for the manufacture of tires having a low rolling resistance; as examples of such silicas, mention may be made of Ultrasil 7000 silicas from Degussa, Zeissil 1165 MP, 1135 MP and 1115 MP silicas from Rhodia, Hi-Sil silica EZ150G from PPG, Zeopol silicas 8715 , 8745 or 8755 of the Huber Company, silicas with high specific surface area as described in the application WO 03/016387 .
• the reinforcing alumina (Al 2 O 3 ) preferably used is a highly dispersible alumina having a BET surface area ranging from 30 to 400 m 2 / g, more preferably between 60 and 250 m 2 / g, an average particle size of at most equal at 500 nm, more preferably at most equal to 200 nm.
• aluminas "Baikalox A125” or "CR125” (Baikowski company), "APA-100RDX” (Condea), "Aluminoxid C” (Degussa) or "AKP-G015" (Sumitomo Chemicals).
• inorganic filler suitable for use in the rubber compositions of the invention, mention may also be made of aluminum (oxide) hydroxides, aluminosilicates, titanium oxides, carbides or nitrides of silicon, all of the reinforcing type as described in the documents WO 99/28376 (or US 6,610,261 ) WO 00/73372 (or US6,747,087 ) WO 02/053634 (or US2004-0030017 ) WO 2004/003067 , WO 2004/056915 .
• the reinforcing inorganic filler used in particular if it is silica, preferably has a BET surface area of between 60 and 350 m 2 / boy Wut.
• An advantageous embodiment of the invention consists in using a reinforcing inorganic filler, in particular a silica, having a high BET specific surface area, in a range of 130 to 300 m 2 / g, because of the high reinforcing power of such charges.
• a reinforcing inorganic filler in particular a silica, having a BET specific surface area of less than 130 m 2 / g, preferably in such a case of between 60 and 130 m 2. / g (see for example requests WO03 / 002648 or US2005-0016651 , and WO03 / 002649 or US 2005-0016650 which also teach the use of reduced amounts of zinc, between 0.5 and 1.5 phr, in combination with silicas of low specific surface area).
• the physical state in which the reinforcing inorganic filler is present is indifferent whether in the form of powder, microbeads, granules, beads or any other suitable densified form.
• the term "reinforcing inorganic filler” also refers to mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers as described above.
• this level of reinforcing inorganic filler will be chosen between 20 and 200 phr, more preferably between 30 and 150 phr. More preferably still, in particular when the composition of the invention is intended for a tread of a tire, the level of reinforcing inorganic filler is chosen to be greater than 50 phr, for example between 60 and 140 phr, in particular in a field from 70 to 130 phr.
• the BET surface area is determined in a known manner by adsorption of gas using the method of Brunauer-Emmett-Teller described in "The Journal of the American Chemical Society” Vol. 60, page 309, February 1938 , more precisely according to the French standard NF ISO 9277 of December 1996 [multipoint volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160 ° C - relative pressure range p / po : 0.05 to 0.17].
• the CTAB specific surface is the external surface determined according to the French standard NF T 45-007 of November 1987 (method B).
• Coupling agents in particular silica / diene elastomer have been described in a very large number of documents, the best known being bifunctional organosilanes bearing alkoxyl functions (that is to say, by definition, "alkoxysilanes") to as functions "Y” and, as functions "X", functions capable of reacting with the diene elastomer such as for example polysulfide functions.
• TESPT bis (3-triethoxysilylpropyl) tetrasulfide
• the TESPT known for a very long time, is considered still today as the product bringing the best compromise in terms of safety to roasting, hysteresis and reinforcing power, for rubber compositions reinforced with a reinforcing inorganic filler such as than silica. It is in this respect the reference coupling agent of a person skilled in the art for tires loaded with low rolling resistance silica, sometimes referred to as “green tires” for the energy saving offered (or " energy-saving "). saving Green Tires " ) .
• This TESPT coupling agent is not suitable for the compositions of the invention which are free or substantially free of zinc, the invention having revealed that the latter require in particular the use of a specific silane polysulfide corresponding to the formula (I) above.
• Such a compound of formula (I) is known and has been described in particular in the application WO 2004/033548 (or US2004-0129360 ) as a coupling agent in rubber compositions loaded with an inorganic filler such as silica, for crown reinforcement (or “belts”) of tires.
• Z groups having from 1 to 18 carbon atoms represent in particular an alkylene chain, a saturated cycloalkylene group, an arylene group, or a divalent group consisting of a combination of at least two of these groups. They are preferably chosen from C 1 -C 18 alkylenes and C 6 -C 12 arylenes; they may be substituted or interrupted by one or more heteroatoms, chosen in particular from S, O and N.
• Such a silane has for example been described, as well as its synthesis, in the patent applications WO 02/30939 (or US6,774,255 ) and WO02 / 31041 (or US2004-0051210 ) and in the application WO 2004/033548 (or US2004-0129360 ) above.
• silane-polysulfide corresponding to formula (I)
• the number x is then an integer, inclusive preferably in a range of 2 to 8.
• disulphides, trisulphides, bis-monohydroxydimethylsilylpropyl (or bis-propyldimethylsilanol) (formula II) or bis-monoethoxydimethylsilylpropyl (formula IV) disulfides, trisulphides, and mixtures of these polysulfides are especially selected.
• the synthesized polysulfide is in fact constituted by a distribution of polysulphides centered on a mean value (in mole) of "x" preferably ranging from 2 to 8, more preferably from 2 to 6, even more preferentially included in a domain from 2 to 4.
• the monohydroxy-dimethylsilylpropyl tetrasulfide (S 4 ) of general formula (II), having the particular formula (VI), is used:
• the monohydroxy-dimethylsilylpropyl disulfide (S 2 ) of general formula (II), having the particular formula (VII), can be used:
• MESPT mono-ethoxy-dimethylsilylpropyl
• the monoethoxy-dimethylsilylpropyl disulfide (S 2 ) (abbreviated as "MESPD”) of general formula (IV), having the particular formula (IX), can be used:
• silane-polysulfide compounds of the formulas (I) to (IX) above are well known and described in the prior art, for example in the applications EP-A-680 997 (or US Patent 5650457 ) EP-A-1,043,357 (or CA-A-2,303,559 ) FR-A-2,823,215 (or WO 02/83782 ), or the aforementioned applications WO 02/30939 , WO 02/31041 and WO 2004/033548 .
• the silane-polysulfide content is preferably between 2 and 15 phr. Below the minima indicated, the effect is likely to be insufficient, whereas beyond the maximum recommended, we observe generally, more improvement, while the costs of composition increase; for these different reasons, this content is more preferably still between 2 and 12 phr.
• Another essential feature of the rubber composition of the invention is that it comprises less than 5, preferably less than 4 phr of carbon black, more preferably less than 3 phr of carbon black (in particular between 0.05 and 3 phr). ; it can be totally devoid (or zero pce) of carbon black.
• Suitable carbon blacks are all carbon blacks capable of bringing a black color to the rubber compositions, in particular blacks of the HAF, ISAF and SAF type known to those skilled in the art and conventionally used in tires.
• reinforcing carbon blacks of the series (ASTM grades) 100, 200 or 300 used in the treads of these tires for example N115, N134, N234, N326, N330, N339, N347, N375
• non-reinforcing type because less structured of the higher series 400 to 700
• blacks N660, N683, N772 One could also use as an example non-reinforcing black called "black ink”.
• the carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used.
• the rubber compositions in accordance with the invention may also comprise all or part of the usual additives normally used in elastomer compositions intended for the manufacture of tires, in particular treads, such as, for example, plasticizers or lubricating oils. extension, whether these are aromatic or non-aromatic, pigments, protective agents such as anti-ozone waxes, chemical antiozonants, anti-oxidants, anti-fatigue agents, reinforcing resins, acceptors (for example phenolic novolac resin) or methylene donors (for example HMT or H3M) as described for example in the application WO 02/10269 (or US2003-0212185 ), a crosslinking system based on either sulfur, or sulfur and / or peroxide and / or bismaleimide donors, vulcanization accelerators, vulcanization activators, excluding, of course, zinc-based activators.
• plasticizers or lubricating oils such as, for example, plasticizers or lubricating oils.
• protective agents such as anti-
• these compositions comprise, as preferred non-aromatic or very weakly aromatic plasticizing agent, at least one compound selected from the group consisting of naphthenic, paraffinic, MES, TDAE oils, esters (especially trioleate) oils.
• glycerol the hydrocarbon plasticizing resins having a high Tg preferably greater than 30 ° C, and mixtures of such compounds.
• the overall level of such a preferred plasticizer is preferably between 15 and 45 phr, more preferably between 20 and 40 phr.
• hydrocarbon plasticizing resins it is recalled that the term "resin” is reserved by definition for a solid compound
• reinforcing filler ie, reinforcing inorganic filler plus carbon black, if appropriate
• inert (non-reinforcing) fillers such as clay particles, bentonite, talc, chalk, kaolin, usable for example in sidewalls or tire treads colored.
• compositions may also contain, in addition to the coupling agents, coupling activators, covering agents (comprising, for example, the only Y function) of the reinforcing inorganic filler or, more generally, processing aid agents capable of in a known manner, by improving the dispersion of the inorganic filler in the rubber matrix and by lowering the viscosity of the compositions, to improve their ability to use in the green state, these agents being for example hydrolysable silanes such as alkylalkoxysilanes (especially alkyltriethoxysilanes), polyols, polyethers (for example polyethylene glycols), primary, secondary or tertiary amines (for example trialkanol amines), hydroxylated or hydrolyzable POSs, for example ⁇ , ⁇ -dihydroxy-polyorganosiloxanes (in particular ⁇ , ⁇ -dihydroxy-polydimethylsiloxanes), fatty acids such as, for example stearic acid
• the invention also relates to a method for preparing a rubber composition based on a diene elastomer and a reinforcing inorganic filler, free or substantially free of zinc (ie, containing less than 0.5 phr of zinc) and having an improved green processability, characterized in that at least one diene elastomer is incorporated by kneading at least one inorganic filler as a reinforcing filler, a polysulfide silane of formula (I) above and from 0 to less than 5 phr, preferably from 0 to less than 4 phr of carbon black.
• the rubber compositions of the invention are manufactured in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first phase of work or thermomechanical mixing (sometimes referred to as “non-phase” phase). -productive ”) at high temperature, up to a maximum temperature of between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C, followed by a second phase of mechanical work (sometimes called phase” Producer ”) at a lower temperature, typically below 120 ° C, for example between 60 ° C and 100 ° C, finishing phase during which is incorporated the crosslinking system or vulcanization.
• a first phase of work or thermomechanical mixing (sometimes referred to as "non-phase” phase).
• -productive ) at high temperature, up to a maximum temperature of between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C
• a second phase of mechanical work sometimes called phase” Producer ”
• all the basic constituents of the compositions of the invention with the exception of the vulcanization system, namely the reinforcing inorganic filler, the coupling agent of formula (I) and the carbon black are intimately incorporated, by kneading, with the diene elastomer during the first so-called non-productive phase, that is to say that it is introduced into the mixer and kneaded thermomechanically, in one or more steps, at least these various basic constituents until reaching the maximum temperature between 130 ° C and 200 ° C, preferably between 145 ° C and 185 ° C.
• the first (non-productive) phase is carried out in a single thermomechanical step during which all the necessary constituents, the possible coating agents, are introduced into a suitable mixer such as a conventional internal mixer. or other complementary additives and other additives, with the exception of the vulcanization system.
• the total mixing time in this non-productive phase is preferably between 1 and 15 minutes.
• the vulcanization system is then incorporated at low temperature, generally in an external mixer such as a roller mixer; the whole is then mixed (productive phase) for a few minutes, for example between 2 and 15 min.
• the vulcanization system itself is preferably based on sulfur and an accelerator.
• Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur especially those selected from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS”), N-cyclohexyl-2-benzothiazyl sulfenamide (abbreviated “CBS”), N, N-dicyclohexyl-2-benzothiazyl sulfenamide (abbreviated “DCBS”), N-tert-butyl-2-benzothiazyl sulfenamide (abbreviated "TBBS”), N-tert-butyl -2-benzothiazyl sulfenimide (abbreviated as "TBSI”) and mixtures of these compounds.
• a primary accelerator of the sulfenamide type is used.
• vulcanization system may be added, incorporated during the first non-productive phase and / or during the productive phase, various known secondary accelerators or vulcanization activators, excluding zinc and any derivative zinc such as ZnO, such as, for example, fatty acids such as stearic acid, guanidine derivatives (in particular diphenylguanidine) and the like.
• the sulfur content is preferably between 0.5 and 3.0 phr, that of the primary accelerator is preferably between 0.5 and 5.0 phr.
• the final composition thus obtained is then calendered, for example in the form of a sheet or a plate, in particular for a characterization in the laboratory, or else extruded in the form of a rubber profile that can be used, for example, as a tread. tire for passenger vehicle.
• the vulcanization (or cooking) is conducted in a known manner at a temperature generally between 130 ° C and 200 ° C, for a sufficient time which may vary for example between 5 and 90 min depending in particular on the cooking temperature, the system of vulcanization adopted and the kinetics of vulcanization of the composition under consideration.
• the filler (silica and optional carbon black) is introduced successively into an internal mixer, filled to 70% and whose initial tank temperature is approximately 60 ° C, the coupling agent, the diene elastomer and the various other ingredients with the exception of the vulcanization system.
• We then conduct a thermomechanical work (non-productive phase) in a stage, which lasts in total about 3 to 4 minutes, until reaching a maximum temperature of " fallen" of 165 ° C.
• the mixture thus obtained is recovered, cooled and the vulcanization system (sulfur and sulfenamide type primary accelerator) is incorporated on an external mixer (homo-finisher) at 30 ° C., mixing the whole (productive phase) for a time. appropriate (for example between 5 and 12 min).
• compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties, or extruded in the form of treads.
• carbon black is used at a level of between 0.1 and 2 phr.
• Composition C-5 is the only one according to the invention since it is devoid of (totally) zinc (or zinc derivative), incorporating less than 5 phr of carbon black and a monofunctional silane of formula (I). More specifically, this monofunctional silane is the preferred silane of formula (VI) indicated above:
• Tables 1 and 2 give successively the formulation of the various compositions (Table 1 - rate of the different products expressed in phr), their properties before and after baking at 165 ° C. for 15 minutes (Table 2).
• Composition C-6 constitutes the reference (“Green” tires), conventionally using zinc oxide as a vulcanization activator (at 1.5 phr of ZnO correspond to 1.2 phr of Zn), carbon black. at a standard rate of 5 phr and the silane TESPT as coupling agent.
• Tables 3 and 4 give successively the formulation of the various compositions (Table 3 - rates of the various products expressed in phr), their properties before and after baking at 165 ° C. for 15 minutes (Table 3).
• the invention finds particularly advantageous applications in rubber compositions intended for the manufacture of tire treads, in particular when these treads are intended for tires for passenger vehicles, motorcycles or industrial vehicles of the heavy truck type.
• Table 1 ⁇ / b> Composition No: C-1 C-2 C-3 C-4 C-5 SBR (1) 69 69 69 69 BR (2) 31 31 31 31 31 31 silica (3) 81 81 81 81 81 silane (4) 6.5 6.5 6.5 - - silane (5) - - - 4.3 4.3 plasticizer (6) 16 16 16 16 16 plasticizer (7) 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12
• Composition No: C-1 C-2 C-3 C-4 C-5 Properties before cooking Mooney (UM) 92 99 94 101 94 Toasting time T5 (min) 12 6 7 8 11 Properties after cooking : Shore A hardness 68 67 66 67 66 M100 (MPa) 1.96 1.99 1.92 1.87 1.81 M300 (MPa) 2.34 2.56 2.50 2.24 2.12 M300 / M100 1.2 1.3 1.3 1.2 1.2 Breaking stress (MPa) 21.7 20.4 21.4 21.5 20.4 Elongation rupture (%) 496 454 469 566 538 tan ( ⁇ ) max 0.33 0.33 0.32 0.32 0.30 .DELTA.G * 5.3 4.3 3.9 4.0 3.3 Composition No: C-6 C-7 C-8 C-9 C-10 SBR (1) 70 70 70 70 70 70 BR (2) 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30
• Composition No: C-6 C-7 C-8 C-9 C-10 Properties before cooking Mooney (UM) 1.06 114 111 108 100 Toasting time T5 (min) 14 7 8 13 18 Properties after cooking : Shore A hardness 67 68 68 66 65 M100 (MPa) 1.9 2.2 2.2 1.9 1.9 M300 (MPa) 2.4 2.8 2.7 2.2 2.2 M300 / M100 1.3 1.3 1.2 1.2 1.2 Breaking stress (MPa) 21.1 20.2 20.5 22.4 20.2 Elongation rupture (%) 524 438 460 517 515 tan ( ⁇ ) max 0.33 0.33 0.33 0.30 0.29 .DELTA.G * 4.4 3.8 4.1 3.0 3.1

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=35220548

Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (30)

Family Cites Families (23)

• 2005
  • 2005-07-28 EP EP05772236A patent/EP1773938B1/fr not_active Expired - Lifetime
  • 2005-07-28 AT AT05772236T patent/ATE506405T1/de not_active IP Right Cessation
  • 2005-07-28 DE DE602005027575T patent/DE602005027575D1/de not_active Expired - Lifetime
  • 2005-07-28 JP JP2007523018A patent/JP5501563B2/ja not_active Expired - Fee Related
  • 2005-07-28 WO PCT/EP2005/008181 patent/WO2006013056A1/fr active Application Filing
  • 2005-07-28 US US11/658,676 patent/US9303148B2/en not_active Expired - Fee Related

Also Published As

Similar Documents

Legal Events